1. A very new board, all of one BIOS/UEFI version available. A future BIOS may support all your memory.
2. The only Patriot memory listed in the Memory Support List that is closest in speed to yours is: PXD38G1866ELK.
3. Are you setting your memory to it's full, 2400 speed? If so, don't, let it default to whatever speed, or set it to 1333 or 1600 when all of it is installed.
4. With two DIMMs installed at a time, run CPU-Z, and take screen shots of the SPD and Memory tabs. Compare all the specs to be certain that the two separate kits you have match specs. I have seen it happen in the past, where two "identical" kits made at different times had different speed and timing settings data, which when combined can cause odd results.